Interdisciplinary Course – “Water”
Five Environmental Science Labs Proposed for “Water” (DODGE, REBECCA)
1. Risk Assessment
Water scientists use risk assessment to characterize the nature and magnitude of health risks to humans
(residents, workers, recreational visitors) and ecological receptors (birds, fish, wildlife) from chemical
contaminants and other stressors that may be present in the environment. A stressor is any physical,
chemical, or biological entity that can induce an adverse response. Stressors may adversely affect
specific natural resources or entire ecosystems, including plants and animals, as well as the environment
with which they interact. Scientists have developed tests to see if various substances, whether harmful
or beneficial, naturally occurring or not, are present in water. These tests, which are part of risk
assessment, involve the use of tools to measure substances or properties that humans cannot sense
directly. However, the general public does not have access to such tools for testing and must often rely
on their senses for risk assessment. Our senses provide the first line of defense to water contamination,
which can occur by various transmission pathways (e.g. through surface water, groundwater, and food).
In this laboratory exercise students will use their five senses to evaluate water containing various nontoxic contaminants. The purposes of the lab are 1) to show that pollutants are not always obvious and
2) to show that not all contaminants pose a health risk. Students will record and analyze observations.
2. Water quality impact on freshwater macroinvertebrates
Macroinvertebrates can tell us a lot about the conditions within a water body. Many macroinvertebrates
are sensitive to changes in pH, dissolved oxygen, temperature, salinity, turbidity and other changes in
their habitat. Habitat is a place that includes everything that an animal needs to live and grow. It
includes food resources, the physical characteristics of the environment, as well as places and materials
to build nests, raise young and keep them safe from predators. Habitats include rocks, sticks, dead and
decaying vegetation and other living organisms such as plants.
When studying Freshwater Macroinvertebrates we want to estimate biodiversity, examine the ecology
of the water body and explore relationships among water chemistry measurements and. Most often it is
impossible to count all individuals of every species present in a habitat. So, we take samples of
organisms in habitats, and calculate the diversity found in these samples to estimate true biodiversity in
the habitats. Biodiversity is the number of different kinds of organisms in an ecosystem and the number
of individuals of each kind. Often biodiversity is estimated from species data, but it can also be the
number in broader categories like the number of different kinds of arthropods.
In this laboratory exercise students will observe microscope slides of water, identify macroinvertebrates,
determine biodiversity and species present in virtual “ponds” to determine water quality conditions.
3. Water sampling in the field; Calibration and collection protocols
Water quality measurements are often conducted in the field, at water sampling sites designated as
critical habitats or at sites used by humans for recreation. Testing kits and instruments must be
calibrated and certain types of sampling must be done on site.
In this laboratory students will learn calibration protocols as well as protocols for observing dissolved
oxygen, temperature, electrical conductivity, pH, and water transparency in a field setting. Students will
observe at diverse sites, record, analyze, and present data, and compare results with teams from
multiple sites.
4. Water treatment and management: field trip to local treatment/management facilities
Water treatment facilities in municipalities typically include drinking water and wastewater treatment
plants. Drinking water comes from variable sources including streams, reservoirs, and groundwater.
Wichita Falls drinking water comes from water reservoirs and is treated and distributed from the
Cypress water treatment facility. Wichita Falls’ wastewater treatment plant purifies water and
discharges it into a local stream. Water for local industrial and irrigation purpose comes from the Red
river and its tributaries; this water is managed by the Red River Authority located in Wichita Falls.
In this laboratory students will visit two of these facilities for an educational tour led by a plant operator
of water manager. Student will work in groups to develop questions for the tour leaders concerning
water treatment and management in Wichita Falls and north Texas.
5. Water Infiltration: from the surface water zone to the groundwater zone
Water that falls on the surface of the Earth may runoff into streams, but runoff may be delay for a
period of time as water infiltrates into surface materials. The infiltration process varies with soil
properties.
In this laboratory, students will time the flow of water through soils with different properties and
measure the amount of water held in these soils. They will also experiment with the filtering ability of
soils by testing the pH of the water before and after it passes through the soil and observing changes to
the clarity of the water and to the characteristics of the soil. Students will also identify the physical and
chemical changes that occur as water passes through soil. Students will be able to design experiments
that test soil and water properties. These activities will take place in the laboratory. Students will
construct dual-ring infiltrometers to enable the measurement of water infiltration into soil. Student
observations will show that the infiltration rate of water into soil changes depending upon the level of
soil saturation. Students will graph and analyze data to concerning soil infiltration effects on runoff and
flooding.